Stimulation of prolactin secretion by L-3, 4-dihydroxyphenyl-serine (L-DOPS) via central norepinephrine in the rat

Abstract Intracerebroventricular (icv) injection of L-3, 4-dihydroxyphenylserine (L-DOPS) (50 and 250 μg/rat) raised in a doserelated manner both plasma prolactin (PRL) and CSF norepinephrine (NE) in urethane-anesthetized male rats. Intravenous (iv) injection of larger doses of L-DOPS (5 and 10 mg/100 g BW) slightly but significantly increased plasma PRL and CSF NE. L-DOPS injection (50 μgat, icv or 5 mg/100 g BW, iv) also raised plasma PRL in conscious rats. There was a good correlation (r = 0.74) between CSF NE and peak plasma PRL in the anesthetized animals. Propranolol (100 μg/100 g BW, iv) inhibited plasma PRL responses to L-DOPS (50 μg/rat, icv) and NE injection (1 μg/rat, icv) raised plasma PRL in anesthetized animals. These findings indicate that L-DOPS stimulates PRL secretion via central noradrenergic mechanisms in the rat.